Furnace



Jan. 27, 1942. T. A. BOOTH v 2,271,168

FURNACE Filed June 6, 194C 3 Sheets-Sheet 2 .In rev 72V',

T. A. BOOTH Jan. 27, 1942.

FURNACE Filed June l6, 194C 3 Sheets-Sheet 3 Patented Jan. 27, 1942 FURNACE Tom -Askew Booth, London, England, assigner to n VStein & Atkinson Limited, London, England, a

company of Great Britain Application Junev, 1940,Seria1No.,339,l9=7 InGreat Britain July '5, 1939 6 Claims.

The invention comprises improvements in or relating to metal melting or heating furnaces and isconcernedwiththat type of furnace (hereinafter-referred to as of the type set forth) in whichheating .isjeflected by means of internally red 3 tubes positioned in the lower part of the interior of the furnacevwh'ere they are submerged in 'the metal.

It isa particular objectfofthe invention-tc provide in a simple manner for the easy cleaning and/or repairing of the tubes and of the'interior of a furnace of the type set forth. A further particular object of the invention is to provide a furnace of the said type which is suitable for the heating ofaluminium and its alloys.

According to the present invention, a furnace of the type set forth has the heating -tubes mountedin a wall of the furnace and said wall adapted for being moved away from the rest of the furnace.

In one suitableconstruction, the wall in which the heating ytubes Vare mounted is adapted for being moved bodily away from the rest of ythe furnace toadetached position. l

Several heating tubes, suitably' of vhairpin shape, may be'mounted in an end wall through which they :pass to occupy anormal position along the bottom ,of the :furnace and the said wall may be arranged so that'itcan be moved away until the tubes are completely withdrawn from the interior of the furnace.

According to another construction, the-wall in which, the heating tubes are mounted is .hinged to the restpof the ,-furnace, for example, to the bottom; part, j-so that it may be'moved by a hing- Advantageous embodiments of the invention will now be more fully 'described by way of example and "with reference tothe accompanying drawings wherein: v

Figure l1 is a sectional yelevation of a furnace in which the end wall carrying the heating tubesr is movable 4bodily away from the other walls.

Figure 2 is a sectional plan of Figure 1. Figure 3 is a sectional plan View illustrating thefen'd ywall of Figures land 2 moved away from the furnace body.

n Figure 4 is avsectional elevation of va furnace having' the end wall carrying the heating tubes hinged to the furnace body, and

Figure 5 is a plan of Figure 4 but with the lid of the furnace'removed.

In the "particular example shown in Figures 1 to 3, vthe furnace is a fixed furnace of rectangular shape, but it is to be understood that the invention is also applicable to movable furnaces and to furnaces of round or other shape. In Figures l to 3, the walls of the .furnace are lined with a'layer I 'of refractory material backed with insulating Vbrick 2 supported by a metal framework. An arched roof 3 of insulating brick is supported on the walls and, if desired, sealed against them with the aid of a sand seal as at 4. The whole of the furnace with the exception of one end wall 5 is mounted on a supporting grid of .girders 6. The necessary lined openings may be variously arrangedin the walls of the furnace. For example, a downwardly inclined filling spout 1 may be arranged in one side wall above a drain spout (not shown), whilst a tapping spout 8 is provided in the opposite wall and a'large skimming opening 9 in thel other end wall. This last opening may also be used for charging solid material into the furnace, but the lling spout y1 should be used for the introduction of molten metal.

'I'he end wall 5 is mounted with its own lining yIIJ infa U-shaped metal frame II which emto the furnace body. The end wall 5 is supported in its frame II upon `the rear part of a fourwheeled carriage I1 capable of running on guide rails I8 extending forwardly from the end of the Ybody of the 'furnace so that this end wall may be moved bodily away from the other walls of the furnace to a detached position such as is shown in Figure 3 when desired. At the top, the end wall 5 may normally engage under a projecting part of the roof yas may be seen from Figure 1.

Heating tubes III passing through and secured in theend wall 5 normally extend along the full length ofthe furnace near its bottom as shown in Figure A1. The tubes-are advantageously such as are described in the specifications of British Patents Nos. 452,204, 469,114, 487,764 and 488,101 with a burner at one end and an exhausting means or eductor at the other end. Preferably, and as shown, the tubes are of hair-pin form, for instance such as are disclosed in the second of the above specifications. In this case, the hair-pin tubes may be disposed closely side-byside and on edge as illustrated, the lower limbs being connected to the burners and the upper limbs to the exhausting means. A gas main 2|! and an air-supply main 2| for the burners, and an exhaust hood 22, all common to all the tubes I9 are mounted above the front part of the carriage I1. These conduits 20 and 2| have readily breakable joints at 23 with xed apparatus, a motor driven fan in the case of the air-supply main being shown at 24 in Figures 2 and 3.

Normally, the tubes extending into the furnace rest near the ends upon supports therein, such as transverse ribs 25 of refractory lining material formed on its bottom. When the end wall 5 is moved bodily away from the other walls of the furnace, the tubes I9 will also require further support. This may be provided by a cross-bar 26 temporarily placed on pedestals 21 at the sides of the rails I8 so that it lies between the partially removed end wall 5 and the end of the furnace body. The end wall may then be removed so far that the tubes are completely withdrawn from the furnace as shown in Figure 3 and both the tubes and the interior of the furnace are thus rendered readily accessible for cleaning.

In the example illustrated by Figures 4 and 5, the invention is shown applied to one form of movable furnace, in this case a tilting furnace. The tilting takes place about the axis of the shaft 28 and upon an arcuate runner 29 movable on rollers such as 30. The tilting may be effected by hand-driven worm and Worm-wheel gearing 3|.

In this example, one end wall 3| of the furnace is hinged to the furnace body B at 32 upon a bracket 33 secured to the frame 3'4 at the bottom of the adjacent end of the furnace body. The hinging may be eected by hand-operated gearing including a screwed rod 35 pivotally connected at 36 to a bracket 31 on one side of the end wall and extending through a bracket 38 fixed on the frame 34. The rod has a handwheel 39 applied to it on the far side of the bracket 38 and there is suitable iiexibility in the parts so that, with rotating of the handwheel, the end wall 3| may be moved away from the furnace body by hinging about the axis 32 and the parts may, for instance, assume the position shown in dot and dash lines. Obviously, the lid 40 of the furnace would be removed when hinging of the end wall 3| is effected and for this purpose it may be mounted on wheels 4| movable along rails 42. The interior of the furnace and the heating tubes 43 are fully accessible when the lid 40 isV removed, and the end wall 3| hinged away, from the furnace body. Some of the heating tubes in this example are shown on edge and one, the central one, is placed flatwise. Other arrangements of the tubes may be adopted, however, if desired. The end wall 3| is closed on to the body by tightening the handwheel 3'9 and when closed it may be secured by swing bolts 44. The tapping spout of the furnace is shown at 45, pouring by this spout being possible when the furnace is tilted. 'Ihe connections of the gas and air supplies to the corresponding conduits for the heating tubes would in this construction suitably be of flexible nature.

To ensure a good joint between the movable end wall 5 or 3| and the adjacent end of the body of the furnace, the surfaces to be brought in contact with each other may be covered with a layer of fire-clay. To facilitate breaking of this joint when the end wall is to be moved, screw-jacks may be arranged in the said wall s0 that they can be turned to exert pressure against the bottom and side walls of the furnace and force the end wall away.

An alternative and preferable jointing means consists in providing the flange I2 of the end wall frame Il, Figures 1 to 3, or the ange I3 of the frame I4 of the furnace body, or the similar flange 46 or 41 on Figures 4 and 5, with a depression 48 or 49 respectively extending along its length to receive a sealing material, such as sand as at 50. Preferably, and as shown, both the flanges I2 and |3, or 46 and '41 have oppositely disposed depressions 48 and 49 to form tunnels to receive the sealing material 50. The complementary depressions may conveniently form together circular channels one in each of the side walls which terminate at their lower ends in a transverse circular channel extending across the bottom of the furnace to the outer faces of the furnace walls. The sealing or packing material, such as moulding sand, is tamped tightly into the tunnels or channels.

Sometimes a difficulty is experienced with these furnaces in that, due to unequal expansions, spaces may be produced between the walls of the heating tubes and the wall of the furnace in which they are mounted so that there is a tendency for molten material in the furnace to leak through. The present invention also has for its object a construction by which the dimculties of such a leakage may be overcome and to this end a trough 5| may be provided on the outside of the end wall 5 or 3| of the furnace and this trough be filled with sealing material 52, such as moulding sand. The bottom of the trough 5| is f provided with one or more doors (not shown) through which the sealing material may be removed when desired. Should it be found that there is leakage of molten material from the furnace the sealing material 52 is tamped more securely round the heating tubes.

What I claim is:

1. A metal melting or molten-metal heating furnace comprising a furnace chamber having a side opening, a closure-forming movable wall normally closing said opening, an internally-fired heating-tube apparatus mounted in said wall and constructed to normally extend inwardly therefrom along and over substantially the Whole area of the lower part of the chamber interior and to be submerged in the metal within the chamber, and mounting means for said wall rendering the same movable away from adjoining Walls of thel furnace with the heating-tube apparatus moving therewith from its normal location within the chamber.

2. A furnace according to claim 1, wherein a trough charged with solid sealing material proof substantially against leakage of molten metal is provided on the movable wall and extended about the region thereof where the heating-tube apparatus passes through said Wall so that said sealing material contacts with said heating-tube apparatus.

3. A furnace according to claim 1, wherein the heating-tube apparatus is mounted in a, movable end Wall of the furnace chamber and this Wall and the side and bottom walls of the furnace chamber have abutting surfaces all formed with depressions which in the closed condition of the movable Wall co-operate to provide channels, said channels being lled with a solid sealing material proof substantially against leakage of molten metal.

4. A furnace according to claim 1, wherein the heating-tube apparatus is mounted in a movable 10 end Wall of the furnace chamber and the means mounting said Wall is arranged so that this Wall can be moved until the tube is completely Withdrawn from the interior of the furnace chamber and wherein supports on which said heating-tube apparatus rests are provided in the furnace chamberand other supports on which said heating-tube apparatus temporarily rests are provided outside said chamber.

the bottom of the furnace and having the heating tube apparatus mounted therein, and means for moving said end Wall to its open or closed position.

TOM ASKEW BOOTH, 

